


A Christmas Theory

by GayforKristenGayforKate



Category: Ghostbusters (2016)
Genre: Bi-Curiosity, Bisexual Erin Gilbert, Canon Lesbian Relationship, Christmas, Christmas Eve, Christmas Fluff, Erin Gilbert is a useless gay, Erin Gilbert/Jillian Holtzmann Fluff, Erin's trying so hard, F/F, Fluff, Fluff and Humor, I just love these two and want them to be happy every day for the rest of forever, Lesbian Character, Mistletoe, Slow Build, Slow Build Erin Gilbert/Jillian Holtzmann, Slow Burn, Tooth-Rotting Fluff, Useless Lesbians, poor little baby, slow-ish
Language: English
Status: Completed
Published: 2018-12-28
Updated: 2019-01-03
Packaged: 2019-09-29 02:15:59
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 12,943
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17194601
Author URL: https://archiveofourown.org/users/GayforKristenGayforKate/pseuds/GayforKristenGayforKate
Summary: Erin wants to kiss Jillian Holtzmann like nobody's business, and she's figured out a way to do that with little to no consequences, but she only has a few hours to pull it off before Holtz goes home for Christmas.





	1. A Kiss Missed

**Author's Note:**

> Hi guys! I know its a little after Christmas, but I literally thought of this Christmas Day, plus, I like to drag the holiday out until January 1st, so there's that. This was supposed to be a one shot, but I got carried away, as always. I have a bunch of chapters finished, and I was going to post them all at once, but I couldn't wait any longer, so here you go! Enjoy the Christmas fluff! <3

Today was the day. It was Christmas Eve and Erin had a theory. She had figured out a way to put that theory to the test, but today was the only day to do so, and, like most instances in her life, she was getting nervous. 

 

Over the past couple of months Erin had come to two realizations, the first being that she liked girls. She liked them in the soft, snuggly, lovey way, where the idea of spending an evening curled up on the couch with a girl watching Netflix and cuddling made her feel giggly and tingly in a way she’s never felt before. She also liked them in the hot, steamy, sexy way, where the notion of being pressed up against a wall, passionately kissed, and touched by a woman made her see stars. She was very attracted to women.

 

Her second realization came to her much more abruptly. About a week after realizing her attraction to the same sex, still barely even admitting it to herself, she was slammed with the image of Holtzmann in her underwear. She had made her way upstairs to the third floor of the firehouse to do a load of laundry, when she found the blonde standing in front of the washing machine in a black sports bra and rainbow boxers, staring at her phone.

 

She let out the tinest gasp and almost dropped her laundry basket when the engineer turned to face her, “Hey Gilbert,” she smiled, as if being half naked in front of her colleagues was a normal occurrence for her.

 

“H-hey Holtz… Um, why… why are you in… your… why are you… like that?”

 

Holtzmann looked down, almost as though she had forgotten, “Oh! Funny story, I was working on some new ectoplasm preservation methods, and one of the chemicals I was using spilled on my clothes. What a ding-a-ling, right?” she laughed, “It’s a harmless chemical, but I was wearing my favorite X-Files shirt, so I wanted to get it all in the wash before the stains set in.”

 

“Ohhh, okay…” Erin responded, trying to keep her eyes focused on anything but Holtzmann’s breasts. Or her stomach. Or her arms. Or her butt.

 

“Did you wanna toss your stuff in with mine?”

 

“Oh, sure! Thanks,” Erin said, noticing she was still awkwardly standing in the doorway holding her basket. Holtz opened the washing machine for her and she tossed in all her clothes.

 

She was about to go back downstairs to her desk and take a breath for the first time in five whole minutes when Holtzmann said, “Oh, wait! Come here, I wanna show you something!” The blonde hopped up and sat on the washing machine and motioned for Erin to come sit next to her as she pulled her phone back out.

 

 Erin sat next to Holtz, the vibrations of the washing machine doing nothing to help her feel less aroused, when the engineer pulled up a video of a cat, “He’s wearing little booties!” She cackled loudly.

 

Erin was attracted to Holtzmann. Big time.

 

It wasn’t just point-blank attraction either. After about two months of secretly gawking at the blonde, she had also come to recognize that her fascination with her colleague had blossomed into a full-fledged crush. And it was major. She didn’t know how to approach any of this. Here she was silently suffering every time the engineer moved or spoke or breathed, but what was she supposed to do?

 

Surely, she couldn’t tell Holtzmann how she felt, because that would be inappropriate. They worked together. If the outcome was poor, then she had just ruined both a work relationship _and_ a friendship. A _best_ friendship! This was where her theory would come into play.

 

Erin was sitting at her desk this Christmas Eve morning with a sprig of mistletoe in her hand. Her theory being that if she could just get Holtz and herself into a situation where they might be forced to kiss, i.e. mistletoe, then one thing might lead to another and she might find out that Holtz feels the same way about her. On the flip side, if they kiss and nothing stems from it, she’ll feel a little bit more capable of moving on at the very least.

 

Holtz had been up in the lab all night long, fixing one of the proton pistols that had gotten severely smashed up during their last bust. On days when the blonde had pulled an all-nighter she would usually force herself to get breakfast around 9am, so Erin knew that she had at least 20 minutes to hang her mistletoe and finally test her theory. She decided that the most convenient spot would be the entranceway to the kitchen, so she grabbed a thumbtack from her desk and got to it.

 

…

 

She studied the little sprig that was now dangling overhead, praying that this plan would work. Holtz was going home for the holidays later this evening, so she figured this would be her only shot. Her heart skipped a beat when she heard Holtzmann’s music stop. _Here we go_ , she thought to herself. She hurried over to the kitchen table to grab her mug of coffee, and then sprinted back to the kitchen entranceway, leaning her body against the wall in a way that she hoped looked cool and casual.

 

She sipped her coffee as Holtzmann made her way out of the lab and downstairs, “Hey Holtz,” Erin smiled, nervously, as the blonde reached the last step.

 

“Hey, E,” the engineer smiled back, as she walked into the kitchen and opened the freezer.

 

Erin felt a little deflated, seeing that the blonde didn’t immediately start climbing all over her, but she shook her head and told herself that Holtzmann was probably so tired that she couldn’t even think straight. Of course she wouldn’t notice a tiny little branch hanging from the ceiling. She was going to give it another moment or two before she said something about it herself.

 

“How’s the proton pistol coming along?” Erin asked.

 

“She's almost done,” Holtz smiled sleepily back at the physicist, as she popped two Eggo waffles into the toaster, “One of the charge ports still isn’t connecting properly, and the trigger doesn’t seem to be functioning correctly either. It’s giving me some lag,” she yawned, “so I just have to fix those things and then the rest of this wonderful holiday can be spent doing wonderful holiday things!”

 

Erin felt butterflies at the sight of the blonde yawning and rubbing her tired eyes. It was a sight she’d seen a million times before, having spent countless long days and nights at the firehouse with the girls, but now, of course, it made her feel new, peculiar feelings.

 

Just when Erin was going to make another move to guide Holtz’s attention to the mistletoe, Abby and Patty erupted through the front door, gusts of cold wind following, “Whew! It’s really comin’ down out there!” Patty yelled.

 

Erin whipped around to find her friends stripping themselves of their winter layers when Abby said, “The weather lady on the radio said that it could be going down to negative 30 tonight! We might be getting, like, 6 feet of snow!”

 

“Eh, I’ve seen worse,” Holtz said, as she danced around the kitchen, humming ‘Last Christmas’.

 

“Ahhh, my zipper’s stuck, Erin could you help me really quick? I can’t move in this thing,” Abby said, struggling to get her coat off.

 

“Sure!” Erin set her mug down and moved from her spot, over toward the front door.

 

Meanwhile, the toaster popped, signaling to Holtzmann that her waffles were done, so she grabbed them, plopped them on a paper plate and made her way back over to the kitchen entranceway.

 

“Oh hey! Someone stuck some mistletoe up here!” Patty said, as she meandered out of the foyer and towards the kitchen, still shaking some snow out of her hair, “Holtzy, get over here and give Patty some sugar!”

 

“Here I come, Pattycakes!” Holtz bopped over toward the taller woman, waffles in hand, and reached up on her tiptoes, planting a big kiss on Patty’s cheek.

 

Erin practically gaped in disbelief. How had her plan taken such an unexpected turn? It was foolproof, there was only one step: Get Holtz under the mistletoe. But, there went her kiss, snatched away by somebody else. How could she not have taken external factors into account? _Always plan for extraneous variables, Erin._

 

“Okay, ladies, I hate to kiss and run, but I have an incredibly stubborn, incredibly _unfinished_ proton pistol calling my name. See you guys in a few hours!” Holtzmann took a bite of one of her waffles, saluted her friends, and dashed up the stairs.

 

“Um, Erin?” Abby waved a mitten clad hand in front of the physicist’s face, and Erin realized that she had been virtually frozen for about 45 seconds, “Honey, I hate to interrupt whatever’s going on in your noggin, but I’m suffocating over here…”

 

“Oh! Right, sorry,” the redhead continued fiddling with her friends’ zipper.

 

Erin was going to need a new plan, and fast.


	2. Re-Thinking the Plan

**Summary for the Chapter:**

> Wherein the Useless Gay™ in Erin intensifies.

**Notes for the Chapter:**

> Thank you for all the wonderful feedback!! My heart is so happy! <3<3

It had been about an hour since the Mistletoe Debacle of 2018, as Erin was calling it. She didn’t want to let her one chance slip away without a fight, so here she was, sitting at her desk, strategizing. She’d thought about using more mistletoe, but there was no way she’d be able to get any more due to the current weather conditions. She could use the sprig she already had, but, even though this place was decorated to the nines, the girls would surely notice if it were to just up and move to a new spot.

 

She tapped her pencil on the corner of her desk. How could this be so difficult? She knew Holtz, she knew how to get her attention… right? Maybe she should just forego the plan altogether, put on a slinky dress and some heels, and see how the blonde would react to that. Erin stopped and thought for a moment… she decided that that would be Plan B.

 

The physicist continued tapping away at her desk, when Abby called over, “You okay, Er? You sound like the Little Drummer Boy, over there,” she laughed at her own joke.

 

“Yeah, I’m fine,” the physicist dropped her pencil back in the cup on her desk, “Sorry, I was just lost in thought, I guess,” she sat back in her chair, and started unconsciously tapping her foot on the ground.

 

Abby looked down, noticing this, “Well, don’t worry. You’ll figure out those equations soon, you always do,” she smiled and turned back to her own work, “Maybe try taking a break and grabbing a snack. You haven't eaten anything yet today, so you probably just need some good brain food.”

 

“You’re right,” Erin sighed. She hadn’t even thought of her equations, but food sounded a lot more appealing to her than physics, at the moment, “If I’m not back in an hour, it means that I’ve died,” she stood up from her chair.

 

“Okay,” Abby called back, not looking up from her desk, “I’ll make sure we don’t bust your ghost, but contain it, lovingly.”

 

“Thank you.”

 

Erin roamed over toward the kitchen, the mistletoe from earlier staring her right in the face. Taunting her. Laughing at her.

 

“What are _you_ looking at?” She whispered to the twig, when she heard a loud clank come from the second floor. She turned her head to look upstairs when, following the clank, she heard Holtzmann hiss, “Ow, fuck!”

 

She abandoned her brain food, and climbed the stairs to the lab, “Holtz, are you okay?” She found the engineer doubled over, clutching her left hand close to her body, “Oh my god, what happened??”

 

“Nothing, it was nothing,” Holtz sucked in a breath, “this stupid pipe just decided it wanted to fall onto my foot,” she pretended to be calm as she kicked the pipe across the floor, “which, of course, made me jump, so then I burned my hand on those coils.”

 

Erin crossed the lab, avoiding the pipe that rolled in her direction. She approached the blonde, and reached out, “Can I see it?”

 

“It’s fine, really.”

 

“Holtz.”

 

Holtz hesitantly let go of her hand and placed it in those of the physicist. Erin studied it for moment, “Okay, it doesn’t look too bad, but it is bleeding, so just keep it still and let me wrap it up,” she made her way toward the cabinets across the room in search of the first aid kit. She grabbed some bandages, some disinfectant, and the almost empty tube of burn cream, making a mental note to herself to pick up some more.

 

“Okay,” she said softly, walking back toward the engineer. Erin gently took the blonde’s calloused, yet delicate hand in her own, “Just a little antiseptic here,” she hummed quietly, “aaaaand, a little burn cream here,” Holtz glanced lovingly at her for a moment. Erin didn’t notice.

 

“Just gotta wrap her up, aaaand… there! Good as new!” Erin smiled.

 

“Thanks, Er,” Holtz looked her in the eyes, “it feels a thousand times better already.”

 

Erin held her gaze with Holtzmann for a moment or two before she lost her nerve, “Do you- um… do you need help with anything up here?”

 

“Actually yes, now that you mention it,” the blonde lifted her bandaged hand, “I might not be a lefty, but two hands are usually ideal when working around all this daaaangerous equipment,” she sang out her words, spinning back into her spot.

“I wouldn’t be bouncing around so much, you did just burn yourself,” Erin laughed, moving closer to the blonde’s workbench.

 

“Technicalities,” Holtz rolled her eyes, then shot a wink the redhead’s way, “If you want to help though, I would be eternally grateful. All you’d have to do is hold down these little wires,” she moved Erin into place, “and then I’ll come around to this side with my trusty doohickey, here,” the blonde placed herself closely behind Erin, wrapping her arms around to reach the bench, “and then we just have to fuse these tiny doodads together, and boom!”

 

“Boom??”

 

“Not that kind of boom.”

 

“Oh. Also, ‘doodads’? Shouldn’t you be using, like, technical terminology?” Erin asked, holding the wires in place, looking over her shoulder to glance at the blonde.

 

“Eh, I prefer Holtzmann Vernacular,” she smiled, “now hold still, please,” Holtz rested her chin on Erin’s shoulder.

 

Erin did as she was instructed, while the engineer behind her got to work. Having Holtz this close to her was definitely something she wanted, she just hoped it would have been in a substantially different capacity. She supposed she should take what she could get, though, seeing as this was the closest she’d gotten to the engineer all day.

 

She silently observed as the blondes’ hands worked quickly and methodically. She had never really watched Holtzmann work up close before, she realized. It was honestly breathtaking. The tiniest of movements took heavy calculation, and the tiniest of mistakes could be detrimental. Erin wondered how a woman so wild and silly could have the ability to still be so meticulous and precise.

 

Erin had always had incredible respect for Holtzmann and the work she did, but seeing it from this vantage point definitely shifted something inside of her. The woman working behind her was ridiculously talented and absurdly incredible. This did nothing to simmer the plethora of new feelings burning inside of her. As a matter of fact, all this did was intensify her longing that much more.

 

Erin realized where her mind was going, and it was not the time for that. She and Holtz were working around dozens of hazardous materials, and one slip up could spell catastrophe. And besides, no matter how much the physicist wanted so badly to turn right around and crash into the blonde’s rosy pink lips, run her hands through her hair, leave a bruise or two on her neck… rip off her clothes… She needed to stick to the plan… whatever that may be.

 

She redirected her focus back to the engineer’s hands. They looked so soft. She remembered holding one of them a moment ago. They _were_ so soft. She started to wonder what else those hands were good at.

 

“Et voilà!” Holtzmann declared, moving out from her spot to study her handiwork up close.

 

“We’re done, that’s it?” Erin sputtered out, aching at the loss of contact.

 

“Yep! You, my dear, are looking at a fully functioning proton pistol! And I couldn’t have done it without your assistance,” Holtz smiled, making her way over to the couch, raising her left hand up in the air, “and thanks again for fixing Ole’ Lefty!”

 

“It was my pleasure,” Erin blushed, “and hey, now you have the rest of the day free!”

 

“Thank god!” Holtz exhaled, as she plopped down onto the couch and closed her eyes, “This gal needs a long nap.”

 

Erin chuckled, “So, um, what time were you planning on going home tonight?”

 

Holtzmann opened her mouth to reply, when they heard a call from downstairs, “Hey, get your butts down here, we got lunch!!”

 

Holtz hopped up off the couch just as quickly as she fell onto it, “To be continued, cutie,” She grasped the redhead’s hand and pulled her toward the fire pole, “Let’s go see what they could have possibly gotten delivered in this hell storm.”

 

Erin yanked them in the opposite direction, "Ah. Staaaairs, Holtzmann."

 

"Fiiiiiiine."

 

Erin was grateful that Holtz was in front of her so she couldn’t see just how red she had become, simply from holding the blonde's hand. They reached the bottom of the staircase and turned into the kitchen to see Patty and Abby standing next to three boxes of pizza, “Do you love us??”

 

Holtz’s jaw dropped, “No way!”

 

“How did you get someone to deliver pizza in this blizzard??” Erin asked, equally as astonished.

 

Abby replied, “Well Benny also works part time at Giovanni’s Pizzeria down the block, and he owed me a favor. I left him a big tip anyway, though. I’m not heartless, I’m just hungry.”

 

“I hear that! Let’s dig in before we have to go!” Patty said.

 

“Oh yeah, what time were you guys heading out?” Holtz asked.

 

“Well, I’m leaving in an hour,” Patty took a slice, “I wanna get out of here before this damn storm gets any worse, because there is no way I’m missing my flight back to Boston.”

 

“Patty and I decided to share a cab to JFK, so I’m gonna leave whenever she does,” Abby laughed and bit into her slice of pepperoni, “You can still get a last minute Christmas Eve flight with me, Er. Christmas in Michigan? Huh??”

 

“I would, but I’m still not going home,” Erin grew quiet.

 

Patty turned to her friend, “You’re not? How come?”

 

“I kind of wasn’t really invited… I was actually sort of uninvited…”

 

“Why??”

 

“Erin, you didn’t tell me this…” Abby said, concern in her voice.

 

Holtz just gazed at the redhead quietly in disbelief.

 

Erin fidgeted, “Um, it’s my parents, they’re still uncomfortable with the whole ghost thing, I guess, I don’t know,” she exhaled, “It’s okay though, because now I can spend a nice quiet holiday by myself. I won’t have to make small talk with my relatives, I won’t have to suffer through the endless ‘When are you getting married?’s from my great-aunt, and I won’t have to spend five days dodging my mother, it’s great. It’ll be totally fine,” she tried to convinced herself, mostly.

 

“Okay,” Abby said, skeptically.

 

Erin tried to turn the attention away from herself, “What about you, Holtz? When are you leaving?”

 

Holtz took a big chomp into her crust, “My flight is scheduled at 5:15, so I’ll probably be outta here around 4.”

 

Erin felt a knot forming in her stomach. The thought of Holtzmann leaving before she could figure out what to do about her plan made her ache inside. The thought of Holtz leaving at all made her ache even more.

 

“Where’s your family, Holtzy?” Patty grabbed a napkin.

 

“Well, my immediate family lives here in New York, but we’re having Christmas at my aunt’s house this year, she lives in Chicago. My parents flew out a couple days ago, and my sister flew out yesterday, so I’m told I’ll be the last to arrive. Nothing like being fashionably late, am I right?” she elbowed Erin, causing a small smile to spread across her face.

 

Patty finished her last bite and said, “Alright, Abs let’s skedaddle,” she wiped the pizza crumbs off of her hands.

 

“What do you mean skedaddle? It’s only 12:30!” Abby scrambled to check the time.

 

“Hey, I’m not missing my flight. Now move your behind, I’m gonna go call a cab.”

 

Patty was already out of the kitchen and picking up the phone when Abby finally stood up, “Fine, I’m going to grab our bags,” she took another slice of pizza and grumbled up the stairs.

 

Erin and Holtz were left alone in the kitchen, surrounded by three half-empty pizza boxes.

 

The physicist pushed her distressed feelings aside and turned to her friend with as much of a smile as she could muster, “I bet you’re excited to see your family, huh?”

 

“Eh. It’ll be alright, I guess,” the engineer blew a blonde curl out of her face, “I love my parents, and I love my sister, too, but she really knows how to get on my nerves,” Holtz grabbed what Erin estimated to be her fifth slice of pizza, “she’s 6 years older than me, and she has this really fancy job, so she always makes it a point to boast about how well-regarded and celebrated she is in her field.”

 

“You’re extremely well regarded in your field, Holtz. You just gave a speech at CERN last year!”

 

“Yeah, but Carrie’s a dooooctor,” Holtz drew out sarcastically, “Doctor trumps crazy ghost lady every time, apparently. At least at family gatherings, anyway,” the blonde grew quiet.

 

“I know how that feels…”

 

Holtz gave her a half smile, “that, plus, my uncle’s a raging alcoholic, so it’s gonna be a weird holiday,” she laughed.

 

Erin laughed as she reached around the table and gave her friend a hug, “You’re gonna have a great time, I know it.”

 

Holtz pulled back gently and met the redhead’s eyes, “Thanks, Er. You will too…”

 

“Okay! The cab’s gonna be here in 12 minutes, Abby, let’s haul ass!” Patty clapped, trying to hurry her friend along.

 

Abby shuffled down the staircase, lugging five suitcases behind her, “Well I’d be a hell of a lot _faster_ if I had some _help_ ,” she said pointedly.

 

Holtz popped up from her seat, pizza hanging from her mouth, and sprinted over to the stairs to grab some bags from Abby’s hands, “Thank you, _Holtzmann_.”

 

“Hey, you know I’m just messin’ with you, Abs. Here, gimme those suitcases,” Patty laughed, reaching out to help.

 

“Oh, it’s okay. You get to carry them from the cab to the check-in line,” Abby chuckled, releasing the last two bags from her grip.

 

“Touché, you crazy scientist.”

 

Abby and Patty started donning their coats and hats, as Erin stood up from the kitchen table and joined Holtz by the staircase, the two calmly watching on as their friends bickered.

 

"Children," Holtz said, shaking her head.

 

"Mmmmhm," Erin agreed with a smirk.

 

After a solid four minutes of zipping and buttoning, and ‘Ow, watch it!’s, Abby finally turned around and said, “Okay, Holtz, your plane ticket is on my desk, just in case you forget--”

 

“God bless you.”

 

“—and Erin, you call me if you need anything at all, okay?”

 

Patty added, “Same goes double for me, baby.”

 

Holtz leaned over to the physicist, “And you know you can _always_ call me,” she winked.

 

“Thanks guys, I appreciate it,” she turned to the engineer, “And thanks, Holtz, I’ll um, keep that in mind,” she tried to hold herself together and suppress the smile that had sparked.

 

“Okay, you guys have a very Merry Christmas!” The girls all hugged and waved each other goodbye.

 

“We’re definitely doing presents when we get back,” Patty opened the door, letting in heavy gusts of wind and snow, “Holtzy you’re gonna go crazy over what I got you!”

 

“Is it a puppy??” Holtz yelled out the door.

 

"No!"

 

“Be safe!” Erin hollered.

 

“Bye, guys!” “Merry Christmas!”

 

The door closed, and the girls stood there shivering from the cold, when Erin remembered, “Oh, hey! I have some cookie dough in the fridge, do you want to make some Christmas cookies with me before you go?” she asked, pointing in the direction of the kitchen.

 

“You know I could never say no to you, Gilbert. Or to cookies.”


	3. Cookies, Cookies, and More Cookies

**Summary for the Chapter:**

> Erin is a tornado of feelings. Holtz is a tornado of sprinkles.

**Notes for the Chapter:**

> I wrote a rough draft of this chapter a few days ago, but it still needed some tweaking. After reading a Chapter 2 comment by @Holtzexmachina , this chapter now has extra sprinkles! Enjoy! :D

Three batches of cookies later, the girls were covered in flour, and laughing their asses off, when Holtzmann dropped her rolling pin and said, “Wait, wait, wait. Who am I??” she stood up stick straight, with a very serious look on her face, “’The _mayorrrr_ says your paperwork needs to be filled out by Fridayyyyyy…’”

 

Erin cackled loudly, “Oh my god, Holtz stop, I’m gonna pee!”

 

“’We’re just gonna need you guys to put the cat back in the baggggg, mmmkayyyy?’”

 

“Holtz, oh my god,” Erin was laughing harder than she had in a very long time, “If she were here right now, we would all be jobless.”

 

“Oh please, she doesn’t scare me,” Holtz laughed, and went back to rolling her dough, “Ugh, shit, my cookies keep breaking. Erin, help meeee!” she whined.

 

“I told you we should have just used the pre-made dough I had in the fridge!”

 

“That’s no fun.”

 

“Your dough is probably falling apart because it's, like, 94% chocolate chips,” Erin quipped.

 

" _You're_ 94% chocolate chips," Holtz mumbled, smirking.

 

Erin laughed, “Holtzmann, shush. Here, you need more flour,” she said, dusting the blonde’s cutting board.

 

“ _You_ need more flour,” Holtz pinched some flour between her fingers and poofed it onto the redhead’s face.

 

“Hey!” Erin grabbed more flour and dotted the engineer’s nose.

 

“Mmmm, you’re a tough nut, Gilbert. I like that,” Holtzmann winked, and went back to her cookies.

 

“Aren’t you gonna brush that off?” Erin pointed to the blonde’s white-tipped nose.

 

“No, silly. I like it there,” Holtz hummed.

 

Erin giggled quietly, growing a soft shade of pink, as she grabbed a small container from across the counter, “Okay, now Holtzmann. I’m going to give these to you—“

 

Holtz perked up and turned around, “Sprinkles?”

 

”—And I trust that you’re not going to make a mess—“

 

“Sprinkles?”

 

“—Because you’re a grown woman, and you understand how to behave as such.”

 

“Well, I don’t know about that…”

 

“Here,” Erin extended, presenting the engineer with a full, unopened tub of rainbow sprinkles.

 

“Sprinkles!!!!” Holtz took the container from the redhead, opened it up and inhaled deeply, “That’s quality stuff, right there, Gilbert,” she closed the container, and set it on the countertop, “Ugh, you’re the best!!” and she planted a gigantic kiss right on Erin’s cheek.

 

Erin was frozen in her spot, electricity shooting through her entire body, as she watched the blonde dance back over to the cookies. Millions of thoughts were buzzing around inside her head. She wanted to do that again. She wanted to be ready next time. She wanted it to be on the lips, goddammit. But if this was how she felt after only getting a kiss on the cheek, she would like to order one Holtzmann Cheek Kiss to be delivered every single day for the rest of her life. This was a high she never wanted to come down from.

 

Erin stood up straight and fixed her hair, attempting to compose herself, because she knew she must have been redder than tomato. She joked, “Use those sparingly, Holtz,” and she went to open the fridge, “You start mixing the dough for the sugar cookies, I just have to grab some more butter.”

 

The redhead opened the refrigerator and stuck her entire head inside in an effort to cool off. She didn’t know how she was going to get through the rest of the holiday, especially now that every time she so much as glanced at Holtzmann she would remember that kiss, and subsequently lose all control of her motor skills. She took a deep breath, grabbed the butter, and closed the door.

 

She walked back over to their workspace to find Holtz rapidly stirring the dough, sending bits of unmixed ingredients and hundreds of sprinkles flying about. Erin ran her hands through her hair, “Holtz, I love you, but you’re mixing that way too fast,” she laughed, “and… oh my god, did you dump _all_ of those sprinkles in there??”

 

“Look! It’s gay cookie dough!” Holtz held up the bowl, showing the physicist its rainbow contents.

 

Erin shook her head and laughed, “Here, let me just…” she trailed off as she placed her hand on top of Holtz’s and carefully whisked the cookie dough, “If you mix it slowly, the dough binds together a lot quicker,” she said still mixing, her hand still holding Holtz’s.

 

She didn’t even realize she did it this time, it just felt natural. She regretted not making some kind of a move earlier when they were upstairs in the lab, so maybe she could figure out a way to make this plan work right now. It was no ‘mistletoe kiss’, but Erin supposed it might actually work. She moved a little closer to Holtzmann, letting her body lean against the engineer’s. The blonde smelled like cinnamon sugar and motor oil. It was a scent the physicist never wanted to forget.

 

“You really know a lot about baking,” Holtz glanced up at the physicist.

 

“My grandmother and I used to bake all the time when I was little. She taught me a lot,” Erin met Holtz’s gaze.

 

“That’s really cool,” Holtzmann said quietly.

 

The two stopped mixing the dough, still holding each other’s gaze. Erin didn’t want to get her hopes up, but the look on Holtz’s face made it seem as if --

 

_BING!_

 

Holtz jumped, and Erin closed her eyes and inhaled sharply, fully convinced that the universe must have some sort of hidden vendetta against her.

 

“The gingerbread cookies are done!” Holtz danced her way over to open the oven.

 

Erin repeatedly hit her head up against a cabinet, and let out a quiet groan, filled to the brim with frustration and defeat.

 

“Oh, they turned out great! I was pretty concerned there for a minute, considering I added way too many eggs.”

 

“Holtzmann, you’re killing me,” Erin chuckled, turning around to face the blonde.

 

_RRIIINNNNNNNGG!!_

 

The girls were interrupted a second time, this time by the telephone.

 

Holtz took off her oven mitt and tossed it on the counter. She sprinted into the next room and answered the call, “Ghostbusters, this is Holtzmann...”

 

Erin was practically losing her mind. The moment they just had was a great opportunity, and it just _fell into her lap_ , she didn’t even have to plan it out. She wondered if maybe this was a sign from the universe that she should just call it quits. Holtz was leaving soon, and she didn’t know how many more opportunities, if any, she would have before that happened. All she knew was that if she was interrupted any more tonight, she was going to personally send a ghost to whatever higher power was watching her and laughing right now.

 

Holtz sauntered back into the kitchen, while Erin was pouring herself a glass of water. Erin looked up and said, “I’m going to actually start crying if somebody needs us to bust a ghost on Christmas Eve…”

 

“No, no that was just Abby and Patty.”

 

“What happened, is everything okay?” the physicist sipped.

 

“Oh yeah, they’re great. They just called to let me know that they were looking at the flight schedules for this evening, and they saw that my flight was cancelled.”

 

Erin nearly choked on her water, “It was??”

 

“Yup. Too gosh darn snowy out there, I guess,” Holtz leaned against the counter, “One of the televisions in their terminal was playing the news, and they heard that by the time my flight would have left, the city’s going to be in a full whiteout.”

 

“Oh, wow. I’m really sorry that you can’t go home for Christmas, Holtz, that sucks,” Erin said, softly.

 

“It’s okay. Really,” Holtzmann sounded genuinely relieved, “Now I don’t have to put up with my sister and all of the ‘medical breakthroughs’ she’s made since Thanksgiving, and I also don’t have to listen to my uncle’s two cents about ‘the gays’. I just get to stay here with you and have an actual holiday,” she laughed, “And now you won’t be here by yourself! It’s a win-win.”

 

Erin turned red when she realized just how excited the engineer was to spend the holidays with her, “You promise you’re okay?”

 

“Are you kidding? I’m more than okay!” Holtz rubbed her hands together in excitement, “Let’s bake some more cookies, Chef Gilbert! We'll just need some more sprinkles...”

 

Erin laughed, set her glass down, and walked back over to their mess. She was silently thanking her lucky stars for this miracle and apologizing to the higher powers of the world for threatening them with ghosts. The physicist was beyond thrilled that she would get to spend Christmas with Holtzmann. She had not one clue how her plan was going to come together, but somehow, kiss or no kiss, she was going to make sure this holiday was one they would never forget.


	4. Screw the Plan

**Summary for the Chapter:**

> Erin's brain can really go a mile a minute.

“Erin, hurry up!”

 

“I’m coming, I’m coming!”

 

The physicist hurried down the staircase, carrying a massive pile of blankets along with her. She shuffled into the living area to find Holtz crouched in front of the entertainment unit, thumbing her way through dozens of DVDs.

 

“Okay, we’ve got _Home Alone_ , _Christmas Vacation_ , _Elf,_ and _The Santa Clause_ ,” Holtz listed the Christmas movies that the Ghostbusters had in their ever-growing collection.

 

After the girls had finished their seven batches of what could be loosely described as cookies, and Holtz called her family to alert them of her new situation, she suggested the two get cozy and watch some Christmas movies. All Erin needed to hear was the word cozy and she was in.

 

“Oooh, I could go for _Christmas Vacation!"_ Erin said, falling onto the couch, the mountain of blankets burying her in the process.

 

“You got it, hot stuff!” Holtz pulled the DVD from the stack and popped it into the DVD player. She grabbed the remote off of the entertainment unit and plopped down onto the other side of the couch.

 

A beeping sound arose from the other room, and Erin shot back up, “Oh! I almost forgot the popcorn!” She shuffled into the kitchen, now donning a pair of red flannel pajamas and fuzzy white slippers.

 

“Don’t forget the cookies!” Holtz called out to the redhead, also in pajamas, although hers were a little different. The engineer was wearing a festive t-shirt that read, ‘This Is My Gay Apparel’ and a pair of red shorts with candy canes on them.

 

Erin returned, a bowl of popcorn in one hand, a plate of cookies in the other. She set them down on the coffee table in front of them and sat back down on the couch, undeniably closer to Holtzmann than she was before.

 

Erin began layering the blankets across the two of them while Holtz fast-forwarded through the previews.

 

“Here we go!” Holtzmann hit play and the movie began, “Ugh, I’m so glad you picked this one. This was always my favorite Christmas movie, growing up.”

 

“It’s a good one,” Erin laughed. This movie _would_ be Holtz’s favorite, “Mine was always _A Charlie Brown Christmas,”_ Erin blushed.

 

“Yes! That one’s so great! Oooh, and _How the Grinch Stole Christmas_! Animated _and_ live-action!” Holtz was bouncing on the couch as the opening credits rolled.

 

“And _Rudolph the Red-Nosed Reindeer_! I basically love any of those stop motion Christmas movies. They’re so sweet and nostalgic,” Erin snuggled deeper under the blanket.

 

“That they are, darling” Holtz gave a warm smile.

 

Erin was trying so hard not to read too much into body language, but unless her eyes were deceiving her, she could have sworn she saw Holtzmann glance down at her lips. That’s like a universal ‘I wanna kiss you’ sign, right? She looked back over at the blonde to see if it would happen again, only to find her picking a piece of fuzz off of her pajamas and blowing it into the air.

 

The opening credits ended, “Oh, it’s startinggggg,” Holtz sing-songed.

 

The girls watched on as Chevy Chase’s character repeatedly tried and failed to make his family’s holiday a good one, every attempt funnier than the last. What made Erin laugh hysterically, though, was as Clark Griswald was hanging Christmas lights on his house, the ladder fell from underneath him, leaving him suspended from the roof, all of which prompted Holtz to tell the story of how she pulled up to the firehouse a few weeks ago, only to find Kevin in the exact same predicament. 

 

“No way. You’re kidding!!”

 

“He was just dangling there, like a monkey hanging from a tree. Not even breakin’ a sweat.”

 

“Man, I knew he was freakishly strong, but…” Erin chuckled.

 

“I told you he was made in a lab. We have to make it a point to find out if that boy actually has a belly button,” Holtz joked. She reached forward to grab a cookie off of the coffee table, and when she sat back her arm was touching Erin’s.

 

They were sitting up against one another now. This wasn’t good. Well, it was very good, actually, but it wasn’t necessarily ideal. Harmless eye contact was enough to make Erin lose her train of thought, but skin-to-skin contact? She was gone. The physicist tried to continue focusing on the movie, but right now, the only thing her mind could focus on was the fact that Holtzmann’s arm was touching her own.

 

Holtz shifted under the blanket.

 

And now her leg.

 

Erin took a deep breath and thought for a moment. Movies are romantic right? Maybe not this one in particular, but it would have to do. Perhaps if she timed it right, she might be able to get her plan rolling and get her kiss. She wondered when would be the best time to try, and she glanced over at Holtzmann, who was munching on a cookie, and staring attentively at the television. She wanted so much to just reach over and kiss her right on her stupid, beautiful mouth, but she forced herself to wait. This was Holtz; the moment had to be perfect.

 

“He’s gonna fall off the roof,” Holtz said, and three seconds later, down goes Chevy Chase, “Ahhhhh, I love it.”

 

Holtz sunk deeper into the couch and laid her head on Erin’s shoulder. She breathed in for a beat, and then rested her own head on top of the blonde’s.

 

Yeah. Erin was definitely going to wait a while. She wanted to spend some more time like this.

 

 

…

 

 

About an hour, and approximately 52 more movie quotes from Holtzmann later, Erin was feeling a little more confident, although not quite enough. She had been back and forth in her mind, weighing option after option, but she still couldn’t justify deviating from the plan. Straying from the plan left her vulnerable. Sure, she could just straight up confess her feelings to Holtzmann, or follow her gut and kiss her when the moment felt right, but that left the possibility of rejection. At least if a kiss were to take place in a controlled situation, Erin could blame it on the mistletoe, or the… hmmm...

 

_Oh my god, are there no other controlled environments where a kiss is obligatory??_

 

Erin began silently panicking.

 

_That’s it, mistletoe is the only controlled holiday kiss situation. There’s no way this plan can happen without me being left susceptible to rejection. This isn’t going to happen, is it??_

 

The physicist glanced over at the engineer, who was giggling at something that was happening in the movie. Erin softened, and practically forced herself to slow down and reason with her nerves. She’d known the blonde for over two years; did she really think Holtz was going to just flat-out kick her to the curb? Of course not, that woman doesn’t have a mean bone in her body. And besides, who’s to say that Holtz didn’t like Erin back, anyway?

 

 The redhead evaluated the signs.

 

The engineer has flirted with her numerous times, and while she _is_ flirty with practically everyone she encounters, Erin had always noticed something shift in the blonde when they interacted. 

 

Holtz was also constantly doing kind things for the physicist. Like, when Erin was sick last month and Holtz drove all the way across town to get her soup from her favorite restaurant. Or last Valentines Day, when Erin was lamenting about being single and Holtz showed up with a bouquet of daises, her favorite flowers. Also, now that Erin thought of it, she’s pretty positive she hadn’t opened a door for herself since the day they met.

 

But, that could all technically be classified as friend stuff… right?

 

She recalled the events of today. Holtz kissed her on the cheek. Friends do that. She caught Holtz looking at her lips. Friends… do that, too… They were currently snuggling on the couch watching a movie. Close friends do that…

 

Fuck it.

 

Erin had finally decided that she was just going to go for it. She had been sitting through an hours’ worth… scratch that… two years worth of adorable Holtzmann antics, and she just couldn’t take it anymore. She was having so much fun, and while she was nervous as hell, she was also more content and at ease than she had ever felt in her whole life, and all she wanted to do was express that to Holtzmann.

 

This was it. Screw her fears. Screw the plan.

 

“Hey Holtz? I kind of have been wanting to tell you something…” the physicist started, eyes closed, practically shaking, “Um, I just wanted to say that… you are my… absolute best friend… and I have had so much fun tonight, and soooo much fun getting to know you over the past couple of years. I’ve never felt happier or more comfortable with a person in my life, and… I guess what I’m trying to say is… I--” she took a deep breath in, “I…really, really like you, Holtzmann…”

 

Erin paused when she heard a soft snore coming from her shoulder.

 

“Hol--” she looked down at the blonde, “Holtzmann?”

 

The engineer was out cold, almost drooling onto the redhead’s shoulder.

 

 _Amazing,_ Erin thought, _why don’t I just rip my heart out and blast it with a proton gun?_

 

She sighed a deep, guttural sigh. She couldn’t blame Holtzmann for falling asleep; she _had_ been up all night fixing their equipment without a break. Still, if the universe could stop throwing wrench after wrench into her plans, she would appreciate it immensely.

 

Her thoughts were interrupted by a small, sleepy noise that escaped from the blonde, as she snaked an arm around Erin’s waist and snuggled deeper into her side.

 

Erin could scream right now, but that alone virtually made her heart grow three sizes. She giggled quietly to herself, and carefully draped her arm around the engineer.

 

 _It’ll happen,_ she thought to herself, moving a strand of blonde hair out of Holtz’s face, _it’ll happen._


	5. Like Hours

**Summary for the Chapter:**

> Erin is tired.

**Notes for the Chapter:**

> I'm sorry that I missed my update yesterday, I was trying so hard to pump out this chapter but my brain was not working at all. Like, not in the slightest. I probably wrote a page, maybe, but when I re-read it today, literally none of it made sense, so I started over. I think it turned out waaaaay better tonight than last night haha plus its probably the longest chapter yet, so strap in!!

“Holtz?” Erin whispered, nudging the sleeping blonde, who had spent the remainder of the movie gradually sliding down into the physicists’ lap, “Holtzmannnnn…”

 

“Mmmm…” the engineer blinked slowly.

 

“Hey there, sleepy,” Erin giggled.

 

Holtzmann propped herself up on her elbow and rubbed her eyes, “Oh wow, did I really fall asleep?”

 

Erin stretched her legs out, “You did.”

 

“Oh geez, Erin, I’m so sorry. We were in the middle of the movie and everything,” Holtz lamented, rubbing the back of her neck, “How long was I out?”

 

“It’s okay, really. You’ve been awake for so long today, I honestly would have been surprised if you hadn’t fallen asleep,” Erin laughed,  “And besides, you really weren’t out for that long.”

 

That was a lie. After the movie ended, the physicist sat with Holtzmann in her lap for approximately 2 more hours. She had been so tired and she looked so comfortable that Erin just couldn’t bring herself to move, so she sat there and played with the engineer’s hair until her legs fell asleep.

 

“I’m still sorry. But, don’t you worry your pretty little head,” the blonde sat up and stretched, “I’m gonna make it up to you.”

 

Erin blushed, “Holtz, you don’t have to do that.”

 

“Shhhh,” she grabbed the redhead’s hand and pulled her up off of the couch, “Come with me…”

 

Holtzmann led the two out of the living area and into the kitchen. She stood Erin in the middle of the floor, “Close your eyes.”

 

Erin was hesitant, but she did as she was instructed, “You’re not going to ‘make it up to me’ with something atomic, are you?”

 

Holtz didn’t reply.

 

“Your silence is concerning me.”

 

Erin heard the refrigerator door open and close. She could then hear Holtz’s footsteps coming closer toward her. The engineer said softly, “Hold out your hand, please.”

 

Erin did so, and it was met with something she was not expecting in the slightest, “Ahh! What _is_ that?” She asked, referring to the freezing cold, wet sphere that was placed into her hand.

 

“Okay, open!”

 

Erin opened her eyes and looked down to find a ball of frozen snow in her hand, and then looked up to find that the engineer was holding one as well.

 

“Are these…? Do you keep snowballs in our freezer?”

 

“I went outside earlier while you were changing into your pajamas and I made a couple of these bad boys. Y’know, just in case we got bored tonight and wanted to have a snowball fight,” Holtz explained.

 

“A ‘one-snowball-per-person’ snowball fight.”

 

“Exactly.”

 

Erin’s hand was getting numb, so she transferred the snowball into her other hand, “Okay, I’m in, but you have to clean up all the snow when we’re done.”

 

“Deal,” Holtz nodded in agreement.

 

Erin shuffled in her spot and stared at the blonde, “Soooo, when do we— _Ow_!! Holtzmann!!”

 

Holtz had chucked her snowball at the physicist mid sentence, “Oh, did I not say ‘Go’?” she smirked.

 

“I hate you,” Erin laughed, wiping snow off of her torso.

 

“But see, now it’s your turn! Hit me, baby! Anywhere but the face,” Holtz bounced up and down on the balls of her feet.

 

“Is this what Fight Club was about?”

 

“I think so.”

 

“Cool,” Erin said, and she whipped her snowball at the blonde.

 

Holtz yelled, “Ooooh! Fuck, right in the boob!”

 

“Oh god, I’m sorry!” Erin ran over to the engineer.

 

Holtz cackled, pointing at her now slightly see-through shirt, “Look, you can see right through my shirt now!”

 

“Oh, look at that, you sure can,” Erin quietly deadpanned, staring anywhere but the blonde’s somewhat visible left breast. She said a little louder, “We should probably get you a new shirt.”

 

“Oh, don’t even worry about it, this one’ll dry in like ten minutes anyway,” Holtz said, waving her hands in the air dismissively, “And besides,” the blonde motioned to the words on her shirt, “I’m donning my ‘Gay Apparel’. I have to wear it on Christmas, it’s like a law.”

 

Erin bit her lip and glared at the ceiling, averting her eyes from what felt to her to be the only thing she’s ever wanted to look at.

 

Holtz turned to her friend. “You okay, Gilbert?”

 

Erin looked back at the engineer, “Oh. Yeah, just um… cold,” she improvised, “because of, um… the snow.”

 

“Oh! I’ve got just the cure; it’ll warm you up in no time! You just go sit over there,” Holtz pointed to the kitchen table, “and I’ll be over here whipping up my world infamous hot chocolate.”

 

Erin sat down, “Infamous?”

 

“It’s my own secret recipe,” Holtzmann winked, grabbing two mugs from the cabinet.

 

“I’m up for anything, you know that. But, if the contents of that mug are glowing, I’m gonna have to pass,” Erin laughed, and pulled her knees up to her chest, wrapping her arms around her legs.

 

“All of my ingredients are totally legal.”

 

“That doesn’t make me feel better,” Erin studied kitchen table, running her fingers up and down the wood grain, “Legal, doesn’t mean non-toxic, Holtz.”

 

Holtz turned to face the redhead, leaning up against the countertop while the milk was heating up, “Erin, trust me. You’re gonna take one sip of this, and you’ll never be able to drink regular hot chocolate again.”

  

“Is that because all my taste buds will be singed off?”

 

“Mayyyyybe…” Holtz balanced a spoon on her nose.

 

“Fine, but if I develop superpowers overnight, I’m calling Abby and I’m telling on you.”

 

 Holtz laughed and turned back around to pour the hot milk into their two mugs, “Okay, I’m mixing the ingredients now. Avert your eyes.”

 

Erin looked away, instead focusing on a map of New York City that Patty had hung on the wall. She listened as Holtzmann clanked around the kitchen, mixing this and pouring that, a strong scent of chocolate filling the air. She could even swear she heard a small poof, but she told herself it was just her imagination.

 

After a solid minute or two, Holtz pulled up a chair next to the physicist, “Okay,” she sat a mug in front of the redhead, “the moment of truth.”

 

“I’m terrified to drink this, Holtzmann. That should tell you something,” Erin quipped, turning around to face the engineer.

 

“Well I’m going to drink it, too, so whatever happens will happen to the both of us,” Holtz smiled.

 

Erin eyed the mug, “You go first.”

 

“Ugh, fine,” Holtz picked up her mug and took a sip, “Y’know, you really are being way too dramatic about th-“ Holtz’s eyes went wide and she grasped both hands at her throat.

 

“Holtzmann??” Erin panicked as the blonde made choking sounds, “Holtzmann, oh my god!!”

 

The blonde lowered her hands, laughing so hard there were tears in her eyes, “Relax! I’m joking, now will you just drink the hot chocolate?”

 

Erin exhaled, and slumped back into her seat, an exasperated smile spreading across her face that read, ‘I’m actually going to kill you’. She smacked the engineer on the forearm.

 

She picked up her mug and took a small sip, “Oh my god, Holtz…that’s unbelievable! What’s _in_ this??”

 

Holtz looked her in the eyes, “ _Secret_ recipe!”

 

“Holtz, it’s me, who am I gonna tell?”

 

“The government.”

  
  
Erin eyed the blonde, until she gave in.

 

“Gosh, you know I can’t resist those eyes, Gilbert,” she winked, “The secret ingredient is this pepper that I had smuggled in from South America.”

 

“How-“ Erin paused, closing her eyes and pinching the bridge of her nose. Sometimes she really had to prepare herself for the answers the engineer gave her, “How in the _world_ did you do that?”

 

Holtz shrugged, “I know a guy.”

 

“Of course you do,” the redhead took another sip, “So, technically, not _all_ of your ingredients are legal then, huh?” she smirked.

 

“Well, sure, if we’re being ‘technical’,” the blonde put air quotes around the word.

 

Erin sat her mug down on the table, “Wow. You’re right, I will never be able to drink regular hot chocolate ever again.”

 

The engineer took a sip from her own mug, “And you doubted me.”

  

…

 

 

Holtzmann had turned on her Christmas playlist and had it playing softly throughout the firehouse as the two were in the living area relaxing. Holtz was sitting cross-legged on the floor scrolling on her computer, researching materials to buy in order to make what she’d been tentatively calling the Ghost Blender. Meanwhile, Erin was laying on the couch catching up on her book, surprised she was able to focus with the music playing. They had a 10-hour video of a Yule log playing on the television and they were both completely content.

 

“Geez, this place is charging 45 dollars for this part that I need. I could literally find it in a dumpster down the block,” Holtz laughed, “Isn’t that crazy?”

 

“Why doesn’t everyone dumpster dive?” Erin looked over from her book.

 

“Do you wanna come with me sometime?”

 

It wasn’t the date Erin had pictured in her head, but hey, “I mean, sure.”

 

“Really??”

 

The engineer’s eyes lit up in a way that made Erin’s heart sing, “Yeah, it sounds like fun!” she giggled.

 

“Oh, this is awesome! I mean, I love solo dumpster diving, but it’ll be so much more fun with you!”

 

Erin blushed behind her book. She might not particularly like the idea of digging around through garbage, but she really liked Holtz, and that was enough to make her do anything, at this point.

 

“Oh! That reminds me!” Holtz moved to her knees, and propped herself up on the side of the couch next to the physicist, “In my family, we have a sort of tradition that everybody gets to open one present on Christmas Eve. And I really, _really_ want to give you your present tonight, so can we do that?”

 

“Yes, that sounds like fun!” Erin closed her book and sat it on the couch.

 

“Yessss!” Holtz scooted on her knees over to the Christmas tree in the corner of the room, Erin following behind her.

 

The girls sat on the floor and grabbed their respective presents from the pile. Erin looked up at the blonde who was still searching for hers. Time seemed to slow as she watched the engineer, the warm glow of the multicolored Christmas tree lights reflecting off of her hair, softening everything around her. Holtzmann looked like a painting. It was at that exact moment that Erin had realized that her innocent little crush wasn’t so innocent. This crush had turned into something so much more.

 

Erin was sitting there on the floor, across from her best friend, asking herself if she had ever truly felt love before, because if she had, it had never, _ever_ felt like this.

 

“Ahhh, gotcha,” Holtz whispered, as she grabbed her package and placed it in between the two of them, “Okay, who goes first?”

 

“Ummmm… rock, paper, scissors?” Erin asked.

 

“Yes! If you win, you give me your present first.”

 

“Sounds good,” the redhead smiled.

 

Erin threw rock and Holtzmann threw scissors, so the physicist grabbed her present and handed to the blonde, “Here you go,” she grew nervous, “I really hope you like it.”

 

“It’s from you, Er. I’ll love it.”

 

Holtz carefully ripped the paper off and placed it aside to reveal two picture frames, the first one framing a detailed drawing of the four of them together standing in front of the firehouse on move in day.

 

“Erin! This is _beautiful_! Please tell me you drew this,” Holtz said, not tearing her eyes away from the drawing.

 

Erin grew quiet, “I did…”

 

Holtz looked up, “It’s breathtaking, Erin, really,” she smiled, “Thank you _so_ much.

 

The engineer went to set the frames aside, when Erin pointed out, “Um, there’s… actually a second one under there, too…”

 

“Oh, gosh, there is, I’m so sorry,” she sat the first drawing to the side to reveal a second drawing, this one of a selfie Holtz had taken of the two of them a couple months ago. They had their arms around one another and they were making silly faces. It was Erin’s favorite photo of the two of them.

 

Holtz softened, “Oh, Erin…” she looked up at the redhead. Erin could have sworn she saw tears brimming the engineer’s eyes, “I- I don’t know what to say… I-“ she took a breath, “Thank you. I love it so much. This is my favorite picture of us, actually.”

 

Erin’s heart sped up, “I’m glad you like it, I—“

 

“No. I love it,” Holtz reached forward and pulled the physicist into the tightest hug she’d ever received, “Ahh, okay, you’re turn. Although, forewarning, my gift doesn’t even compare to yours.”

 

“You shush,” Erin said taking her gift from Holtzmann, “I can’t wait to see what it is.”

 

Erin tore the wrapping paper off to reveal a box. She opened the box and inside was a piece of scrap metal that was shaped into a ghost.

 

“Holtzmann, this is gorgeous, oh my god,” she took it out of the box, physically unable to take her eyes off of it.

 

“It’s a piece of scrap metal from the subway where we found one of Rowan’s ghosts. Where you almost died, remember?”

 

Erin laughed, “I remember,” she ran her thumb over the metal ghost. She found in the middle, a little red heart that looked like a tiny door, “What’s this?”

 

Holtz smiled, “Open it.”

 

Erin did so, and inside was a tiny vile of… ectoplasm?

 

“That’s ectoplasm from when Gertrude Aldridge ecto-projected all over you at the Aldridge Mansion,” Holtz said, quietly.

 

Erin took the vile out of it’s little alcove and looked at it more closely, “You kept this?”

 

“Of course! You don’t just make a groundbreaking scientific discovery and not keep the proof,” the blonde joked, “Also, that might have been a really important day for the team, but it was also an important day for _you_. That event brought you closer to Abby; it helped reignite your belief in ghosts. That, my dear,” she pointed to the vile, “is some very special ectoplasm.”

 

“It is special,” Erin held the vile close to her heart, and then set it back in its little nook and closed the heart shaped door, “Holtzmann… Thank you so much, I…” she faltered, “I can’t believe you saved these things all this time. This is the most meaningful present I’ve ever received.”

 

 She moved to sit next to the blonde and wrapped her in a long embrace, “Can I tell you something?”

 

“Of course you can, Er,” Holtz cooed.

 

“Okay. When…” she paused, visibly nervous, “…when I told you guys earlier that I was uninvited to my house for Christmas, I kind of lied. I didn’t lie about being uninvited, I just… I lied about… _why_ I was uninvited,” Erin grew quiet. She looked down at the floor for a moment, and then back up at Holtz, “A couple of months ago… I came out to my mother.”

 

Holtz raised her eyebrows, and then placed a comforting hand on the physicists’ knee, gently urging her to continue.

 

“I told her I was bisexual, with a … preference for women… She wanted no part of it. She refused to believe it at first, but I pressed and pressed it into her until she finally understood that I was telling the truth,” Erin took a breath, “My mother told me that I was disgusting and then she told me not to come back to the house.”

  
“Oh, Erin,” Holtz rubbed her friend’s knee, soothingly.

 

“She actually called me a few weeks ago to tell me that they were having the annual Christmas party at their house, but that I shouldn’t bother attending, because I’d just make everybody uncomfortable,” Erin looked back down at the ground, focusing her attention on a piece of thread coming from her pajama pants.

 

The wind kicked up outside, rattling the window.

 

“Erin?”

 

The redhead looked back up, her eyes welled up with tears, one rolling down her cheek.

 

“Oh, Er-bear, come here,” she pulled the physicist close, resting her head on her shoulder, stroking her hair, “You are… _far_ … from disgusting. And anyone who could possibly think that is the one with the problem, not you. You are intelligent, talented… _stunningly_ beautiful…and… if there’s any person in this world or in any other world who chooses to not associate themselves with you, then they’re missing out on knowing one of the best humans in existence.”

 

Erin pulled back, looking Holtzmann in the eyes, “Do you really think that, Holtz?”

 

“Of course I do. The moment you walked into the lab at Higgins, my entire life changed for the better,” Holtz paused, “I’m so thankful that I know you, Erin.”

 

“I’m thankful to know you, too, Holtzmann.”

 

Erin knew her eyes weren’t playing tricks on her this time. Holtzmann looked like she was leaning in. Like, to kiss her. To actually, _finally_ , kiss her. Erin told herself it was now or never and, whether Holtz was leaning or not, she decided to bite the bullet and slowly leaned forward, gazing at the engineer. She was afraid. The woman in front of her was remarkable.

 

When she looked at Holtzmann she saw eccentricities. She saw beauty. She saw strength, and a sense of humor one could only dream of having. She saw everything in her eyes and more.

 

And then she saw nothing.

 

The sound of electronics powering down filled the room, the lights going out, the Christmas playlist cutting out.

 

Erin leaned back, “Oh, for fuck’s sake.”

 

“Oh god,” Holtz felt around, as the room went completely black, “The wind must have knocked the power out. Hold on, I’ll go see if I can flip the breaker.”

 

Holtz got up and slowly moved to the back of the firehouse to find the fuse box.

 

Erin sat in her spot, surrounded by dark, feeling a wealth of emotions. Her stomach hurt. Her heart hurt.

 

She was done.

 

Clearly this was not meant to happen. If it were, it would have happened by now. At least that’s what Erin thought. She was too tired to go through this any more tonight.  
  


The lights came back on very dimly and a moment later, Holtz returned to the room, “Okay, so the power is like ‘out’ out, but I got the backup generator to work, so that’s good,” she noticed the redhead sitting by the tree, looking small, “Hey… are you okay?”

 

Erin stood up, “Yeah,” she said, “I’m just really tired.”

 

“It is getting pretty late,” Holtz knew that wasn't really what was bothering the redhead, but she glanced down at her watch, “do you wanna call it a night? Head up to bed?”

 

“I think that would be nice,” Erin said quietly, looking at the ground.

 

The girls shuffled up the stairs slowly, still not being able to see very well. They made their way into the bathroom and brushed their teeth in silence, eventually moving out into the hallway in front of the doors to their respective bedrooms.

 

Holtz looked over at the physicist, “I had a really great Christmas Eve with you, Erin.”

 

“I had a great Christmas Eve with you too, Holtz. And thank you again for my present, I love it… so much,” Erin’s voice wavered faintly.

 

“I love my present, too,” Holtz paused for a moment, before walking over and hugging the redhead, whispering into her ear, “Sweet dreams, Er.”

 

Holtz released her friend, who looked up at her, “Sweet dreams, Holtz.”

 

Holtz squeezed Erin’s hand before she moved back toward her own door. They entered their rooms and closed the doors behind them.

 

Holtz placed Erin’s drawings on her bedside table, crawled into bed, leaving the dim light on. She pulled the covers up over herself and rolled onto her side. She stared at the drawing of her and Erin. She stared for what felt like hours.

 

Erin kicked her slippers off angrily. She sat down on the edge of her bed and put her head in her hands as if she were about to cry. But she couldn’t. She didn’t have the energy to cry. She turned her light off and crawled under her covers. She stared at the ceiling. She stared for what felt like hours.

**Notes for the Chapter:**

> I'm so sorry... these poor little nerds are really feeling it tonight...


	6. Fueled by Love

**Summary for the Chapter:**

> The One Where Erin and Holtz Finally Figure Their Shit Out.

**Notes for the Chapter:**

> So, I just wanted to say thank you to everyone who read this story, because I really enjoyed writing it <3 And an extra special thank you to those of you who left me such sweet comments! They really made my days brighter and they seriously made me want to give you all the biggest hugs! *Virtual huuuugs!!!* I'm definitely coming back to write more, this was so much fun, and I love these dum dums more than anything!
> 
> *Just a little side note, I wrote and re-wrote this chapter like 2,000,000 (3) times, and every single time, it turned out sooooo angsty. So, I really hope you guys like this ending XD

The clock on Erin’s wall had been ticking for an eternity. Or, at least, that’s how the physicist felt. She refused to look at the time because she didn’t want to actually know how long she’d been awake, but she’d been counting the ticks. If her math was correct, she’d been lying in her bed staring at the ceiling for roughly 2 hours and 47 minutes.

 

2 hours and 47 minutes of going over every single move she’d made today. Recalculating, rethinking what she could have done differently, how she could have possibly made her signs clearer. And then asking herself what if she _didn’t_ need to make her signs any clearer? What if Holtzmann could see her signs from space, but she just flat out wasn’t interested??

 

2 hours and 47 minutes of kicking herself for not noticing just how wonderful the day  _actually_ was. For being blind to the fact that if she wasn’t so hung up with her stupid theory, she could have actually been present. She could have just simply enjoyed the time she got to spend with Holtz if the little voice in the back of her mind wouldn’t have been so concerned with everything going perfectly.

 

2 hours and 47 minutes of visualizing what the kiss could have been like, had any parts of her plan worked. Envisioning Holtz seeing the mistletoe, supplying some witty remark, and just pulling Erin in and kissing her. No hassle, no fuss. Imagining herself confessing her feelings to Holtzmann during the movie, _before_ she fell asleep. Picturing herself throwing all her worries to the wayside and just kissing Holtz under the Christmas tree. A perfect moment ruined by the stupid blizzard.

 

Although, truth be told, she really should have been thankful that there even _was_ a blizzard, because without it, Holtz probably would have flown to Chicago hours ago, leaving Erin stuck in the empty firehouse alone on Christmas.

 

Alone.

 

Without Holtzmann.

 

Without her striking blue eyes, pools that Erin had gotten lost in numerous times. Without her wondrously messy hair, tangled about in that mesmerizing up do. Without her beautiful sense of humor, picking up Erin’s spirits, even in her darkest of moments.

 

Erin exhaled. She finally tore her eyes from the ceiling and rolled over to her side. This was going to be a long night.

 

…

 

Holtzmann had studied every single detail of Erin’s drawing of the two of them, down to each individual hair. Not one was out of place. It was virtually perfect. The engineer had no idea that her best friend even _had_ this talent. Though, now that she thought back, she did always notice Erin doodling at her desk when she got sidetracked. But, she couldn’t believe she never noticed just how astounding those doodles were.

 

Speaking of not noticing things, Erin was bisexual! How had she not seen _that?_ She knew that the physicist was very good at hiding things from the world that she didn’t want to be seen, but even so, Holtzmann’s gaydar was usually a lot more accurate.

 

God, what else had she been missing?

 

Holtz rolled to her other side, the dim light from her bedside lamp illuminating the wall ever so slightly. She kicked her feet out from under the covers.

 

 _Erin_.

 

Holtz closed her eyes.

 

The physicist seemed so sad earlier after the power went out. Holtzmann couldn’t quite figure out why, but something just didn’t feel right. She thought they were having a really great time opening presents, but maybe there was something going on that the engineer couldn’t see.

 

Holtz had had enough of wondering. She tore the covers off of herself and made her way over to the door.

 

Right when she opened it, she was surprised to see the redhead in question standing on the other side, looking like she was just about to knock.

 

Erin let out a small gasp.

 

“Erin! I was actually just about to come and see y—“

 

The physicist had lunged forward, grabbing the blonde by the face with both hands and pulling her into a deep kiss that was fueled by anger and frustration. By confusion and by doubt. By lust and wanting. By love.

 

The kiss was over as quickly as it started. Erin pulled back to find Holtz rigid with shock.

 

The physicist stepped back. She quickly looked away, “Oh god, I’m... I’m sorry…” she backed up a hair more,  “that was inappropriate, I… I don’t--”

 

Erin was interrupted by soft lips gently pressing themselves against her own. Hands slipping around her waist, pulling her in closer.

 

Holtz leaned back slightly, whispering to the redhead, “Hi there,” she smiled.

 

“Hi…” Erin blushed.

 

“That was…”

 

Erin swallowed cautiously.

 

“…really fucking amazing…”

 

“R-Really??” The redhead asked, almost speechless.

 

“Yes, really! What spurred that on?” Holtz asked, sweetly.

 

“Um,” Erin rubbed the back of her neck, “I just really wanted to do that for… a _long_ time,” she laughed, quietly.

 

“You have?” It was Holtzmann’s turn to sound surprised now.

 

“Yeah,” Erin reddened, “I’ve been wanting to do it for a while, actually, but I finally worked up the nerve to do it today. I was hoping to do it before you left, but everything just kept getting in the way, and then we found out that you weren’t leaving, and th—“

 

“Woah, woah, there, cutie,” Holtz pulled them over to sit on her bed, “take a breath. Can you start from the beginning?”

 

Erin exhaled, “Well, a couple of months ago, I realized I that I like girls… and then a little bit after that, I realized that I _really_ like you… I didn’t know what to do about it because I didn’t want to risk our friendship if you didn’t feel the same way, and… I was just… incredibly confused, and scared.”

 

Holtz took her hand.

 

Erin looked down, at the sight before her. She glanced back up at Holtz and smiled so brightly she was practically glowing, “And so, I came up with sort of a theory. The theory was that if I could get the two of us into a situation where we had to kiss, but it wouldn’t be weird, then maybe that could lead somewhere. So, I hung up some mistletoe, because I figured it would be the perfect no-risk situation to initiate a kiss.”

 

Holtz’s eyes widened, “ _That’s_ where that mistletoe came from! My god, I was wondering about that the entire time I was in the lab… y’know before I injured myself,” she laughed, holding up her still bandaged hand.

 

Erin giggled, “and then the rest of the day was just filled with horrible, confusing attempts to woo you…”

 

“ _Woo_ me?” Holtz smirked.

 

“Shut up,” Erin grinned.

 

“Woo me, how?” the engineer implored.

 

“Um…god this it’s so embarrassing,” the redhead shook her head.

 

“Try me,” Holtz winked.

 

“I tried to kind of hold your hands when we were baking cookies… or… I don’t know, it was sort of like a _Ghost_ pottery moment…” she groaned out of humiliation.

 

“I thought that was cute!”

 

“You did not!” Erin playfully shoved the blonde.

 

“I _did!_ C’mon, what else?”

 

“Um, I actually told you how I felt about you today…”

 

“You did? When??”

 

“We were watching the movie. I was unaware, however, that you had already fallen asleep,” Erin cringed at the memory.

 

“I’m so sorry, Erin!!” Holtz squeezed the physicist’s hand, “Ugh, I can’t imagine how you must have felt after that!”

 

“It's okay, it was just one of the most mortifying moments of my existence," she smirked, "I'm kidding. The worst though, was after we opened the presents. I thought I saw you leaning in to kiss me, and so I kind of started to lean in, too… and that’s when the power went out, and I was just beyond done at that point,” she laughed.

 

“Erin?”

 

The redhead looked up, “Yeah?”

 

“I did lean in…”

 

“You… You did? You mean I wasn’t just imagining that??” disbelief spread across the physicist’s face.

 

Holtzmann chuckled, “No, silly, you weren’t just imagining it,” she smiled, sweetly, “I’ve actually been wanting to do that for a while, too.”

 

“You _have_??”

 

“Yeah… I was kind of trying to _woo_ you, myself, today,” the blonde giggled nervously.

 

Erin groaned and fell over onto the bed beneath her, “Oh my god, that’s it. That’s all I can handle. I’m dead,” she laughed.

 

Holtz grabbed her arm and pulled her back up, “Ohhhh no you don’t. Now it’s my turn to admit some things to you.”

 

Erin giggled, “When on _earth_ did you try to woo me today?”

 

“Can we please stop saying woo?”

 

“Yes.”

 

“Thank you,” Holtz laughed and gave the physicist a quick peck on the cheek, “Um, so, upstairs in the lab, when you offered to help me finish the proton gun… I didn’t necessarily need to work from behind you," the blonde flushed, “I guess I sort of pulled a _Ghost_ pottery move myself,” she put her hands over her face, and laughed.

 

Erin sighed, amused, “This is killing me, I hope you know. All of these missed opportunities have shaved years off of my life.”

 

“Ohhh, we’re not done! I made you my world infamous hot chocolate, I snuggled up to you on the couch, I tried to show you my boob,” she counted on her fingers, “I invited you to go dumpster diving me!”

 

“And I accepted!”

 

“…You’ll still go with me though, right?”

 

“Of course!” Erin said, matter-of-factly, “Maybe just not for our first date,” she said, shyly.

 

“ _Our first date_! Wow, Gilbert, are you asking me out on a date right now??”

 

“Um… maybe…” the redhead blushed.

 

“Well, I humbly accept,” Holtz flashed a million watt grin, “Although I do have one more thing to admit, since we’re being honest, here.”

 

“What’s that?”

 

“Well… do you remember when Abby and Patty called me earlier today and told me my flight had been cancelled?”

 

“Of course,” Erin said, curiously.

 

“Well, that kind of… never happened…”

 

“What??”

 

“Yeah, that was actually the mayor on the phone.”

 

Erin sighed and pinched the bridge of her nose, “Okay, we’ll get back to that later," she scooted closer to the blonde and gently rubbed her knee. She asked, softly, "Why did you lie about your flight being cancelled, Holtz?”

 

“I didn’t want to go. I mean, of course I would have been happy to see my family and all that, blah blah blah…” she said, “But... I really, really wanted to stay here with you. That’s it. Plain and simple. Just you.”

 

“Wow… I can’t believe it,” Erin shook her head.

 

“I know…”

 

“We are the two _dumbest_ people alive.”

 

“ _I_ _know!_ ”

 

The girls laughed for a moment and the redhead rested her head on the engineer's shoulder.

 

Erin said, “Well, all jokes aside, I’m really glad you stayed Holtz.”

 

The blonde smiled tenderly, “I’m glad I stayed, too.”

 

Erin looked up, pausing for a moment. She glanced down at the Holtzmann's rosy lips, and then she leaned in slowly.

 

Holtz leaned in, gazing lovingly into the physicist's eyes.

 

Erin leaned further.

 

The two were close to kissing, when Holtz interrupted, “Okay, just so we’re clear, you _are_ leaning in right now, right?”

 

The physicist laughed loudly, “Just to be safe, I think we should assume from now on that I’m _always_ leaning in."

 

“Okay, cool,” The girls kissed softly, and then just remained for a moment’s time, both of them only wanting to hold one another. After the events of the day, simply savoring the warmth of one another’s embrace was all they needed.

 

“Hey, Holtzmann?”

 

“Yeah?”

 

“I really don’t want to interrupt this moment… but I kind of feel like I haven’t slept in weeks," the redhead said, quietly.

 

Holtz chuckled, “Don’t worry, I’m with you there. Do you wanna stay in here? Christmas Eve sleepover??”

 

“I’d really love that.”

 

The girls crawled under the covers and into each other’s arms. Erin rested her head on Holtmann’s chest. She exhaled all of her worries from the day into the air, never to give them a second thought. This was where she belonged. Right here. Listening to the heartbeat of her favorite person, while the engineer played with her hair and squeezed her tight.

 

“So, what did the mayor call about, today?” Erin looked up at the blonde.

 

Holtz smirked, “He, uhhh, wanted to give us an award!” she said, sarcastically.

 

Erin chuckled, and played along, “Mmmm, mm-hmm, that makes sense. An award for what, now?”

 

“He wanted to give you and I an award for finally getting our shit together,” she laughed, "I'm kidding, he actually wanted to personally let us know that, even though it's Christmas, our annual numbers are still due by the 28th."

 

Erin put her hand over her heart, "My goodness. What a kind, generous man," she giggled, rolling her eyes.

 

Just then the power turned itself back on, the light in the room getting brighter, the Christmas music softly playing throughout the firehouse once again.

 

Holtz reached over and turned the light out, “Do you want me to go turn the music off?”

 

Erin thought for a brief moment, “No… I like it, it’s nice,” she sighed, more comfortable than she had ever been, “Everything’s perfect.”

 

Holtz kissed the top of her Erin’s head and rubbed her back, “Merry Christmas, Erin.”

 

Erin reached up and kissed Holtzmann, snuggling into the blonde, never wanting to let her go, “Merry Christmas, Holtz.”

**Author's Note:**

> Follow me on Tumblr for more gay shit and more Holtzbert!  
> @gay-for-kristen--gay-for-kate
> 
> I have an insta too, but I'm horrible at updating that...  
> @gayforkristengayforkate


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